I've heard people say that they can smell things through a mask, so that means they are ineffective against coronavirus. This shows a lack of understanding. It's about particle size and pore size of a mask. A mask is going to have holes in between the fabric weave. It's like saying a BB can go through a volleyball net, so that must mean the volleyball net is ineffective for volleyballs or basketballs. A smell molecule is going to go through a mask because it's a very small particle size. Molecules make up proteins, and proteins make up viruses, and viruses will glob together. That will not get through a mask as easily.